The following includes information that may be useful in understanding the present invention(s). It is not an admission that any of the information provided herein is prior art, or material, to the presently described or claimed inventions, or that any publication or document that is specifically or implicitly referenced is prior art.
1. Field of the Invention
The present invention relates generally to the field of trailer hitches and more specifically relates to drawbar and hitch receiver movement eliminating systems.
2. Description of the Related Art
There are many types of trailers that are being pulled by vehicles on highways and roads each day. These trailers range in size from small trailers that can be pulled by family cars, to large trailers for hauling heavy equipment that must be towed by adequately sized trucks having adequate horsepower for pulling the weight. There are many types of apparatuses used for towing trailers also. Commercially, these hitching apparatuses are designed for specific types and weights of trailers, with the most common being of the 5th wheel style. Non-commercially, the most common type of hitch is the drawbar and receiver type of hitch that gained in popularity due to its versatility. This type of hitch generally has a receiver that is made most often of heavy duty square tubing. The tubing may have various types of mounting brackets or straps that adapt it to be rigidly mounted to the towing vehicle. A drawbar having a trailer ball attached in some fashion is generally constructed such that it has a heavy duty square tube portion that is sized to slide within the receiver and be locked into place by a heavy metal pin that passes through aligned holes in both the receiver and the drawbar. The versatility of such an arrangement is that the pin can be pulled and another drawbar having any number of types or sizes of trailer attachments, or even other devices not used for pulling trailers can be coupled to the vehicle. This probably makes this type of hitch the most common.
The drawbar is sized to easily slide into the receiver, using common sizes of readily available square tubing stock. The clearance between the outer surface of the drawbar and the inner surface of the receiver can become problematic when trailers are being towed which have comparatively high weights for the vehicle doing the towing, that have higher centers or gravity, or that have a balance point that is too far forward such as when a trailer is loaded too heavily behind the axle of the trailer. These things should never be attempted, but happen every day anyway to varying degrees. Very small amounts of movement between the drawbar and receiver can result in much larger, uncontrolled movements of the trailer and reduce the safety factor for the driver and others on the road. Various apparatuses have been designed to attempt to compensate for this, such as anti-sway bar devices, but they are very heavy and cumbersome to install and reinstall. An innovation that would greatly improve the convenience or reduce the labor and expense of using a device for this purpose is needed.
Various attempts have been made to solve the above-mentioned problems such as those found in U.S. Pat. No. 7,052,032 to Edward C. Adair, U.S. Pat. No. 6,283,489 to Josef Thomas Hoog, and U.S. Pat. No. 8,328,222 to Leslie Roeber. This art is representative of anti sway trailer hitches. None of the above inventions and patents, taken either singly or in combination, is seen to describe the invention as claimed.
Ideally, a trailer hitch should provide maximum safety and anti-sway tendencies and, yet would operate reliably and be manufactured at a modest expense. Thus, a need exists for a reliable drawbar and hitch receiver movement eliminating system to avoid the above-mentioned problems.